Thailand's King Bhumibol Adulyadej waves as he returns from the Grand Palace to Siriraj Hospital in Bangkok on December 5, 2011 on his 84th birthday. Thailand's king, the world's longest reigning monarch, left the hospital where he has been staying for more than two years and addressed his subjects to mark his 84th birthday.     AFP PHOTO / Pairoj (Photo credit should read PAIROJ/AFP/Getty Images)